PAS-C01 Technology Practice Question
A company is designing a multi-tier web application on AWS. The web tier must scale based on CPU utilization, and the application tier must scale based on request count. Both tiers are deployed in a VPC with public and private subnets. Which combination of AWS services should the company use?
⚠ Common exam trap
Candidates often assume the web tier should use an NLB for high performance, but the ALB is required for HTTP/HTTPS traffic and CPU-based scaling, while the NLB is better suited for the application tier when scaling based on request count at the transport layer.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Application Load Balancer for the web tier and Network Load Balancer for the application tier
The web tier requires an Application Load Balancer (ALB) to distribute HTTP/HTTPS traffic and can scale based on CPU utilization using an Auto Scaling group with a target tracking policy. The application tier needs a Network Load Balancer (NLB) to handle high request counts at the transport layer (TCP/UDP), which is ideal for scaling based on request count per target. This combination allows each tier to use the most appropriate load balancer for its scaling metric and protocol requirements.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Application Load Balancer for the web tier and Network Load Balancer for the application tier
Why this is correct
This is a standard architecture: ALB handles HTTP/HTTPS traffic and can scale based on CPU; NLB handles TCP traffic and can scale based on request count.
- ✗
Classic Load Balancer for both tiers
Why it's wrong here
Classic Load Balancer is legacy and does not support advanced features like path-based routing or target group health checks required for modern architectures.
- ✗
Network Load Balancer for the web tier and Application Load Balancer for the application tier
Why it's wrong here
NLB is not ideal for HTTP/HTTPS traffic because it does not support path-based routing or HTTP header inspection. ALB is better for the web tier.
- ✗
Amazon API Gateway for the web tier and Application Load Balancer for the application tier
Why it's wrong here
API Gateway is designed for API endpoints, not for serving web pages. It is not a replacement for a load balancer in a web tier.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PAS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PAS-C01 exam.